VT CDL Combination Practice Test (2024)

1. What is the emergency air line for?

It supplies air to the trailer air tanks, and controls the emergency brakes on combination vehicles.
It tells you the amount of brake pressure you need to stop the vehicle.
It controls the front brakes of the tractor in case of an emergency.

2. Air brakes:

should be used only when driving on wet roads.
are an effective way to stop large and heavy vehicles.
are prohibited on larger vehicles.

3. A burning tire must be:

immediately removed from the vehicle.
cooled with water.
covered with cloth.

4. A trailer jackknife is more likely to happen when the trailer is:

5. Brake fade results from, and is affected by:

brakes out of adjustment.
excessive heat caused by using the brakes too much.
All of the above.

6. Emergency brakes must be must be held on by:

7. If are being followed closely, you should:

increase your following distance.
change lanes quickly.
decrease your following distance.

8. To test the service brake:

shift your transmission to a low gear, pump the brake pedal three times, then hold it down for five seconds.
push the brake pedal firmly while going about 5 mph.
gently try to pull forward with the trailer parking brake on, then release the brake.

9. The best way to recognize that your trailer has started to skid is:

10. When driving in very hot weather, the heat will increase the chances of:

CDL COMBINATION PRACTICE TEST (VT)